my printer has not been reacting for a couple of days, but I cannot link that to any software update. I have collected a bunch of information, but I am clueless how to isolate the problem. The physical connection between printer and computer seems to be OK, but no device file such as /dev/lpusb or whatever crops up. What does seem to crop up is an additional device file in /dev/bus/usb/002, and one in /dev/char.

This is the information I have collected:

When I run udevadm monitor and then switch on the printer, it outputs the following:

Code:

monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

Well ... I do not have much USB printing experience, I prefer networked printers. All I know is you must have USB printing enabled in kernel or in CUPS, but not both at the same time. Then add verbosity to CUPS logging if normal error log is not helpful.._________________Please learn how to denote units correctly!

What does the CUPS interface say about the state of the printer?
My girlfriend's Brother (Brother as in printer manufacturer) won't work if it was switched on during boot up. Cups will say that the printer is "not ready or turned off". Usually switching it off and on again does the trick in this case; but sometimes I have to re-add the printer in CUPS to get it working again (probably switching it off and rebooting would also work, but this takes longer than just adding the printer again)._________________Kali Ma
Now it's autumn of the aeons
Dance with your sword
Now it's time for the harvest

Interestingly, the time when it was written seems to be exactly the time my printer stopped printing (as per /var/log/cups/pages.log). Then, I discovered that cups had kept the previous version, under the name printers.conf.0, whose contents sounded more like business as usual:

I simply tried out the following (some gut impulse): Replace printers.conf with printers.conf.0. It worked. Everything is back to normal.

I honestly have no clear idea of what happened, but it looks to me as if I had some problem on 19 September, and CUPS decided to disable the whole system to prevent further damage. Or whatever.

So I am relieved now (I had been braced for something much more tedious and uncertain), but if anybody cares to comment, I would certainly be curious. Or maybe this post will help someone else one day?